An inorganic spheroidized particle is generally prepared by passing a raw material powder (having the same meaning as “inorganic powder” as used herein) through a combustion flame (combustion gas) at a temperature equal to or higher than the melting temperature of the raw material powder with a combustion apparatus (gas combustion burner), and melting or softening and spheroidizing the raw material powder in a powder melting furnace. Studies have been conducted for efficiently melting or softening and spheroidizing the raw material powder and stabilizing a high spheroidization percentage thereof.
JP2002-166161 A discloses an apparatus for preparing an inorganic spheroidized particle in which the inorganic spheroidized particle is prepared while keeping an ambient temperature (combustion gas temperature) within a given temperature range in the region of flame formation of a powder melting furnace.
JP2000-346318 A discloses a burner for spherical particles comprising a specified flame keeping plate and a dispersing means having a specified form inside the short tip portion of a feed pipe for a raw material powder.